HEIGHT RESCUE APPARATUS
There is provided a height rescue apparatus (4) comprising a flexible load element (6) for attachment at end (6a) to a safety line (3). The other end is attached to a flexible elongate element (10) wound on a drum (8) which is part of a speed control means. A flexible harness element (7a) is attached to a bracket (11) and is connected to a harness (2) arrangement. The flexible load element (6) is releasably connected to the bracket (11) and is intended to take the fall loads associated with a user falling. After such a fall the load element is released to allow a controlled descent using the elongate element (10) and the speed control means.
This invention relates to a person being arrested following a fall from height whilst attached to fall arrest equipment and also to the rescue of the person following suspension at height as a result of such fall. In particular, this invention relates to a height rescue apparatus that is physically associated with a person whilst working normally at height and also, in the event of the person being arrested and suspended following a fall from height, provides a means for lowering the person to safety whether it be to the ground or some other safe level.
UK Patent Application GB 2414005 discloses a height rescue apparatus comprising a casing, which incorporates a bracket for attachment to a person's body harness whereby the bracket can be releasably attached to a load element attached to a safety line and the safety line may then be attached to a secure anchorage. Various release mechanisms are disclosed including release that is initiated remotely such as by the transmission and receipt of radio signals. The receipt of radio signals may be used to initiate the activation of an actuator that can then carry out the release operation. An example given of a typical actuator is a pyrotechnic actuator that is initiated electrically. When the load element is released from the bracket, elongate that is also attached to the load element is deployed at a speed controlled by a speed control means thereby controlling the descent of the person being rescued.
When a person is arrested after a fall, the bracket for attaching to the person's harness and the load element releasably attached to the bracket should ideally be arranged so that when fall loads of up to 6 kN are applied between the harness and safety line, loading between the bracket and the load element is aligned as closely as is practical in order to minimise any load transference from the bracket to the casing, tending to rotate the casing. Rotation of the casing towards a person whilst being arrested from a fall could injure the person. Also, if the load transference between the bracket and the casing is small, the casing can be a lightweight construction and therefore more comfortable to wear routinely on a harness. A factor complicating load alignment between the bracket and the load element is that a person can fall in various attitudes such as feet first, head first and prone.
UK Patent Application GB 2414005 discloses load elements between the harness and the safety line that are pivotally interconnected in order to minimise load misalignment tending to rotate the casing in different fall attitudes. However, each element and its pivotal attachment needs to be relatively heavy and expensive to manufacture as a result of a requirement for loading between the harness and safety to be sustainable at 22 kN in order to comply with safety margin requirements. The same applies to the construction of the bracket and its release means. Accordingly, one object of this invention is to provide a bracket, harness attachment and load element attached to the safety line that are light weight, simple and cost effective to manufacture and will not present rigid surfaces that could injure a person whilst falling.
Whilst UK Patent Application GB 2414005 discloses electrical initiation of the activation of the release means, there are no detail embodiments for achieving this. Therefore, a further objective of this invention is to provide specific embodiments for the release means.
This invention also discloses methods of attaching the rescue apparatus to a harness in normal use whereby the weight of the rescue apparatus is supported at least in part by alternative means other than the load elements between the harness and the safety line so it can be aligned with the harness to achieve a comfortable arrangement when worn with the harness and also to minimise exposure to being knocked in day to day use. However, the load elements between the harness and the safety are in use in the event of a fall, subsequent suspension and rescue descent.
According to the present invention there is provided a height rescue apparatus comprising a first flexible elongate element releasably secured to a bracket, a second flexible elongate element attached in use to both the bracket and a harness, a safety line having one end attached to the first flexible elongate element, the other end in use being attached to a secure anchorage, a third flexible elongate element being secured at one end to the first flexible elongate load element and at the other end to at least one speed control means, release means for releasing the first flexible elongate element from the bracket such that when the first flexible elongate element is released the first and third elongate elements are able to move relative to the bracket at a controllable speed so as to provide a controlled speed of descent. The use of flexible elongate for the first and second flexible elongate elements enables both elements to align due to their flexibility with applied fall loads whilst minimising the transference of load tending to rotate the bracket. Any or all flexible elongates may be made from modern high strength polymers to provide a substantially lighter solution than metal equivalents and have any suitable cross section and construction. The bracket is typically secured within casing and the casing may be used to protect the speed control mechanism and the third elongate element from accidental damage and weathering prior to the need for the height rescue apparatus to rescue a person suspended at height.
When a person is arrested from a fall from height, the mental and physical demands can be debilitating making it difficult for the person to subsequently operate his or her own height rescue apparatus to initiate the controlled descent to a safe level. It is therefore beneficial, and in some cases essential, to provide for the release operation to be capable of initiation by a second person but without endangering the life of the second person. Accordingly, the height rescue apparatus may have a release means that is capable of being released remotely. Typical embodiments comprise a portable transmitting unit with its own electrical energy source operable to transmit signals such as light or radio waves and normally physically remote from the height rescue apparatus worn on a harness, a receiver capable of receiving said signals that is typically enclosed within the casing of the height rescue apparatus, a source of electrical energy, an electrical switch that may be controlled by the receiver, an electrically initiated actuator to effect the release means, so that when a person is suspended at height requiring to be lowered to the ground, the transmitting unit is operated to transmit signals that are received by the receiver that then controls the switch to send electrical current to the electrically initiated actuator to activate release of the release means. The source of electric energy is typically one or more batteries contained with the casing. In practical trials it has been found that battery weight savings can be made by incorporating a capacitor that can be charged by a relatively small energy source so that the capacitor can then discharge comparatively high energy to initiate the actuator to release the release means. In a further embodiment of this invention, the electrical circuit may be arranged to remain open in normal use thereby preventing electrical energy to drain from the source of electrical energy. However, in the event that there is load between the harness and safety line exceeding a predetermined limit as would occur if someone were suspended, an electrical switch closes to allow the source of electrical energy to energize the electrical circuit. This has the advantage of enabling the electrical power source to be in service for a long duration before being depleted. When several height rescue apparatuses are worn by a group of people using common transmitters, receivers and encoded signals, any release means can only be activated when a person is suspended or applying load between their harness and safety line thus avoiding the possibility of activating the release means in height rescue apparatuses where people are not suspended. Use of common transmitters, receivers and encoded signals also avoids practical complications arising from the need to pair each transmitting unit with a specific receiving unit.
In practical trials, it has been found that a pyrotechnic actuator is a useful actuator for actuating release of the release means because it is capable of delivering a high level of mechanical energy relative to its weight, size and cost. Such pyrotechnic actuators are typically detonated by a mechanical action such as the firing mechanism in a gun or, more usefully, by an electric current that heats a bridge wire that in turn detonates explosive material within the actuator. Electrically detonated types of pyrotechnic actuator typically require relatively small amounts of electrical energy to initiate detonation and are routinely used in the automotive industry to fulfil safety functions such as initiating the inflation of air bags and pre-tensioning safety belts in the event of a collision, and so their development has lead to products that are very reliable and consistent in their performance.
In an alternative embodiment, the height rescue apparatus may be substantially supported by a secure anchorage rather than by a person wearing a harness. In such an embodiment, the height rescue apparatus may comprise a first flexible elongate element releasably secured to a bracket, a second flexible elongate element attached in use to both the bracket and a secure anchorage, a safety line having one end attached to the first flexible elongate element, the other end in use being attached to a harness, a third flexible elongate element being secured at one end to the first flexible elongate element and at the other end to at least one speed control means, release means for releasing the first flexible elongate element from the bracket such that when the first flexible elongate element is released the first and third flexible elongate elements are able to move relative to the bracket at a controllable speed so as to provide a controlled speed of descent. This embodiment has the advantage that a person does not need to carry the height rescue apparatus in use. In this embodiment, the bracket remains substantially stationary relative to the secure anchorage and the first and third flexible elongates move relative to the secure anchorage during the descent. Clearly, a further embodiment is possible where the at least one speed control means may instead be arranged to move relative to the secure anchorage by attaching the first flexible elongate element to the secure anchorage instead of to a safety line attached to a harness and by attaching the second flexible elongate element to a safety line attached to a harness instead of to a secure anchorage. In practice, it is usually preferable for the at least one speed control means to remain stationary with respect to the secure anchorage to avoid the possibility that any speed control means may be damaged if it were to move over an edge or collide with an obstruction.
The invention will now be described by way of example only with references to the accompanying diagrammatic figures, in which:
When flexible elongate 6 is released from bracket 11 in order to lower person 1 to safety after being suspended following a fall from height being arrested, the load that was applied to flexible elongate 6's attachment to bracket 11, amounting substantially to the weight of person 1, is transferred to flexible elongate 10 thereby applying tangential loading on drum 8.
A protruding substantially cylindrical shaft formed about the axis of drum 8 is located in a corresponding substantially cylindrical hole in drum 8 such that drum 8 is able to rotate about the hole in chassis 12. Whilst radial plain bearing 108 is shown located between drum 8 and chassis 12, such a plain bearing may not be required depending on the robustness of the chassis and drum materials when loaded relatively highly in contrary radial directions. The speed of rotation of drum 8 is controlled by a central brake acting effectively between drum 8 and chassis 12 and also a centrifugal servo brake mechanism attached to chassis 12 and interactive with the central brake between drum 8 and chassis 12 to provide dynamic speed control to the rotational speed of drum 8 thereby allowing person 1 to be lowered at a controlled speed of descent. In some embodiments, chassis 12 may also be part of or attached to bracket 11 whereas in other embodiments chassis 12 may simply abut bracket 11 to resist interactive loading from related loading between harness attachment elongates 7a and 7b and flexible elongate 10 when person 1 is being suspended
Bolt 101 has a hexagonal head 101a that is constrained within a hexagonal recess in drum 8 such that bolt 101 and drum 8 are constrained to rotate together about the central axis of drum 8 and also bolt 101 is prevented from moving along the central axis of drum 8 at least in one direction. Bolt 101 has a threaded region 101b that is engaged in a mating threaded region in a specially formed nut 102. Nut 102 passes through the centre of spur gear drive gear 103 and is frictionally adhered to drive gear 103 by means of a brake lining disc 104 and spring washer 105 such that relative rotational movement between nut 102 and drive gear 103 is prevented until opposing torque between nut 102 and drive gear 103 exceeds a predetermined limit. Thrust bearing 106 minimises friction effects between nut 102 and chassis 12. Friction reduction may also be desirable between bolt 101 and nut 102 whereby one or both threaded surfaces may be coated in a low friction material. When drum 8 together with bolt 101 rotate in the direction of tightening the mating screw surfaces between bolt 101 and nut 102, nut 102 will tend to unwind with respect to bolt 101 largely because of insufficient friction between nut 102 chassis 12. Therefore, as drum 8 rotates with respect to chassis 12, drive gear 103 will also tend to rotate in the same direction.
Drive gear 103 intermeshes with one or more further spur gears to drive spur gear 107 in
The use of respective conical surfaces on chassis 12 and drum 8 either side of friction material 13 has several important advantages compared with a conventional arrangement using parallel flat interconnecting braking surfaces. The conical form is significantly stronger in compression along its central axis than parallel flat interconnecting surfaces and the braking resistance is also significantly greater for a given axial compression loading. The mating conical surfaces also tend to assist radial location between the drum and the chassis helping to resist contrary radial loading. Since the height rescue apparatus is normally carried attached to a person's harness, it is critically important that the weight and size of the apparatus is as small as possible. In practice, it has been found that the conical brake arrangement enables the drum to be made from lightweight and low cost plastic materials instead of the heavier and more costly metal alternatives. The amount of material in the chassis can also be minimised. The friction material 13 may be provided in one or more conical or part-conical portions or segments thereof disposed around the periphery of the drum or chassis.
The method of assembly of flexible elongate 7a and 7b to bracket 11 is shown in
The means for releasing the attachment of elongate 6 from bracket 11 is essentially to move pin 15 towards arrester 20 as shown particularly in
The main purpose of pistons 19a and 19b is to minimise the distance required between the arrester end of bracket 11 and the end of arrestor 20 and/or the extent away from bracket 11 of pin 15 after it has been arrested. This is achieved by allowing the pistons to become an effective part of the length of pin 15 whilst it is being propelled towards arrestor 20. However, because the pistons are able to disengage from pin 15 and move away with flexible elongate 6, arrestor 20 only needs to arrest the length of pin 15. In practice it has been found that two pistons readily disengage from pin 15 although other embodiments could utilize one or more than two pistons. Clearly however, in embodiments where there is no particular desired limitation on the distance between the arrester end of bracket 11 and the end of arrestor 20 and/or the extent away from bracket 11 of pin 15 after it has been arrested, the length of pin 15 could be extended to replace pistons 19a and 19b.
Although arrestor 20 and actuator holder are described above as being attached to bracket 11 they may instead be attached to each other with bracket 11 located in between. In a rescue situation arrestor 20 is intended to stop pin 15 after the movement of pin 15 has been resisted by friction resulting at least in part by the suspended load of the person on flexible elongate 6. However, from a safety point of view, arrester 20 should be capable of stopping pin 15 without a person suspended on flexible elongate 6 in case actuator 16 is initiated in an unforeseen accident when a person is not suspended. Arrester 20 may arrest pin 15 in many different ways, one of which is achieved by plastic deformation of arrester 20 by pin 15 as shown in
When a person is suspended and requiring to be lowered to safety, fall switch 31 closes the circuit and allows charge storage capacitor 34 to store electrical charge. The person suspended or another person equipped with a portable radio frequency transmitter such as radio frequency transmitter 45 shown in
Capacitor 34 is used in the electrical circuit because it can be charged by a relatively low performance battery 29 in order to deliver on discharge a relatively high level of electrical energy. This enables the use of a relatively small and lightweight battery having charge status that is not particularly critical except when it is nearing depletion. However, alternative embodiments may use one or more batteries that are capable of delivering sufficient electrical energy without the need for capacitor 34. High performance lithium batteries are predicted to become smaller and lighter as a result of active product development and so such alternative embodiments may become increasingly preferred in the future.
Routine circuit and component checking can be carried out by closing test switch 30 and enabling battery 29 to be connected to the circuit. Radio frequencies other than a predetermined unique encoded signal can then be transmitted from the portable radio frequency transmitter 45 shown in
The radio frequency transmitter 45 in
In an alternative embodiment, there may be no fall switch 31 and the circuit including battery 29 and the radio frequency receiver may be enabled with a simple switch or else remain permanently closed so that electrical energy is continually drawn albeit at low levels from battery 29. Whilst this has the advantage of avoiding the need for fall switch 31 there are also a number of disadvantages. Firstly, there is the need to maintain sufficient charge in battery 29 such as by using rechargeable batteries that are regularly recharged for use. Secondly, there would be no differentiation between a person working normally and a person suspended as was provided by fall switch 31 so that it would be inadvisable to use a common unique radio transmission code across a number of people equipped with height rescue apparatuses. If each person were to require their his or her own unique radio transmission and receipt code, complications could arise in locating and pairing each transmitter with each receiver in an emergency situation particularly if a battery in a critical radio frequency transmitter was depleted. However, if fall switch 31 was used and the unique code was shared across both transmitters and receivers it would be comparatively easy to locate a portable transmitter for use in an emergency.
In typical embodiments it is common for anyone equipped with the height rescue apparatus to carry a radio frequency transmitter that can be used to initiate their own rescue or to initiate a colleague's rescue. However, other embodiments may include a different method for a person to initiate a self-rescue such as by operating an electrical switch that is directly wired to the electrical circuit in the height rescue that could then be operated in a number of alternative ways such as being pushed, pulled and/or operated by means of a pull cord. This would be useful in the event that the person's radio frequency transmitter was not functioning properly or if it were difficult for a person to operate a radio frequency transmitter when suspended in a harness.
When a person is using the height rescue apparatus in normal use, a compression spring not shown in
In
In
In embodiments that include the test function for testing part or all of the electrical circuit operation, it is useful to have a means for recording when the test procedures were carried out as part of any examination in the event that the invention failed to operate correctly. Such a means for recording typically includes a digital clock with date facility and also digital memory to store the time and date that all or some of the test procedures were carried out. Usually, the most significant data recorded is to do with the most recent test procedure although a log of all test procedures can be useful for gaining information on how closely the required testing procedure has been adhered to. The digital clock is normally powered in circuit permanently.
Whilst fall switch 31 in
All electrical components referred to above are standard and in use. However, in order to provide a small and lightweight package for the unit worn on a harness it may be preferable to incorporate much of the electrical circuit and component on a ceramic hybrid circuit with the likely exception of components such as battery 29 and capacitor 34. Such a hybrid circuit may be made to a unique specification.
In
In
In
The attachment between a person's harness and the safety line as provided by the attachments of flexible elongates 6 and 7 (or 7a and 7b) and bracket 11 is required to withstand fall arrest loading irrespective of the various possible configurations and attitudes that a person's body might assume whilst being arrested. For example, a person might fall with feet or head closest to the ground or with the body in a prone or near horizontal disposition. However, it is preferable to minimise any load during a fall that may be transferred to the casing of the height rescue apparatus particularly load that may result in rotation of the casing such that the casing could bear onto the person's body. This could cause injury to the person and also apply significant loading on the height rescue casing itself and possibly compromise the subsequent safe operation of the height rescue apparatus. It is also preferable for the casing of the height rescue apparatus to be of a relatively light construction in order to minimise its weight when carried on a person's harness. Accordingly,
In
Clearly, a further embodiment is possible whereby flexible elongate 6 is attached to the secure anchorage instead of to the person's harness and flexible elongate 7 is attached to the person's harness instead of to the secure anchorage such that when flexible elongate 6 is released from bracket 11, both bracket 11 and casing 5 move away from the secure anchorage. This has the disadvantage that casing 5 would need to be sufficiently strong to resist being damaged if it collided with anything in the descent path or if it traversed an edge during the descent. Also, this further embodiment would result in rescue line being substantially stationary along its length with respect to any static obstruction or edge that it may collide with in the descent path so that the portion of rescue line in contact with any such obstruction or edge would tend to be subject to greater wear than if the length of the rescue line, as would occur in the embodiments in
In
Whilst it is important that the height rescue apparatus is lightweight, it is also beneficial if it is comfortable to wear in conjunction with a harness.
In preferred embodiments, a resisting means is provided to resist movement of flexible pouch 110 relative to harness straps 2a and 2b such that the weight of the rescue apparatus as contained substantially in casing 5 is supported in normal use by flexible pouch 110. In practice, this is significantly more comfortable in use than simply suspending casing 5 by webbing straps 7a and 7b such that casing 5 is free to swing and hang in an awkward manner. As has already been mentioned, bracket 112 may usefully resist movement relative to itself of both harness straps 2a and 2b so that the cross over of harness straps 2a and 2b presenting loop 114 is also resisted from moving relative to harness straps 2a and 2b. Flexible pouch may then be arranged to envelop both harness straps 2a and 2b either above, below or both above and below bracket 112 so that it is also resisted from movement relative to bracket 112. In some embodiments, bracket 112 may be simply incorporated into or be part of flexible pouch 110. An alternative method for resisting movement of flexible pouch 112 may be to attach flexible pouch 110 to harness straps 2a and 2b so that the attachment resists its movement relative to the harness. However, harnesses typically require adjustment to fit different various sizes of people so it may be beneficial to allow each harness strap to move through flexible pouch 112 for adjustment purposes.
When a person is being lowered after having been suspended following a fall, rescue line is unwound at a controlled speed and deployed from an aperture in the casing of the rescue apparatus between both elongate 7a and 7b that are attached to the person's harness. Therefore, it is important that the rescue line is separated from elongates 7a and 7b to avoid any rubbing and potential damage and degradation in the strength of any elongate. In
Any reference above to flexible elongate includes flexible elongate of any useful cross section, construction and material. In practice, it is preferable for the flexible elongate to be lightweight and compact.
The described embodiments may differ in their details but they are linked by common operating principles. Accordingly, it will be understood by the person skilled in the art that the technical features described with reference to one embodiment will normally be applicable to other embodiments.
Where the invention has been specifically described above with reference to these specific embodiments, it will be understood by the person skilled in the art that these are merely illustrative although variations are possible within the scope of the claims, which follow.
Claims
1. A height rescue apparatus having a fall arrest function and a lowering function, comprising a flexible load element releasably held in a first position relative to a bracket, a flexible harness element attached to the bracket to retain a harness, one end of a safety line in use being attached to the flexible load element and the other end of the safety line in use being attached to a secure anchorage, a flexible elongate element being secured at one end to the flexible load element and at the other end to at least one speed control means and release means for releasing the flexible load element from said first position, such that when the flexible load element is released the flexible load element is able to move relative to the bracket at a controllable speed so as to provide a controlled speed of descent.
2. The height rescue apparatus as claimed in claim 1 wherein the flexible load element and the flexible harness element are in the form of webbing straps.
3. The height rescue apparatus as claimed in claim 2 wherein the webbing straps are made from non-metallic material.
4. The height rescue apparatus as claimed in claim 2 wherein the flexible load element provides a first loop for attachment to the safety line and a second loop for attachment to the flexible elongate element.
5. The height rescue apparatus as claimed in claim 4 wherein the flexible load element provides a load loop intermediate the first and second loops for said releasable attachment to the bracket.
6. The height rescue apparatus as claimed in claim 1, wherein the flexible load element is held relative to the bracket by means of a pin which is received in a bore in the bracket and which is adapted to move along the bore to release the flexible load element.
7. The height rescue apparatus as claimed in claim 6 wherein a recess is provided in the bore of the bracket for receiving part of said flexible load element.
8. The height rescue apparatus as claimed in claim 6 wherein the pin is released by pyrotechnic means.
9. The height rescue apparatus as claimed in claim 8 wherein the pyrotechnic means incorporates means for retaining the pin after it has been released.
10. The height rescue apparatus as claimed in claim 9 wherein the retaining means comprises an arrestor at one end of the bore.
11. The height rescue apparatus as claimed in claim 10 wherein the arrestor comprises or includes a deformable material or deforms the pin or a combination of any of these in order to absorb the momentum of the pin.
12. The height rescue apparatus as claimed in claim 6, wherein the flexible harness element forms with the bracket an opening for attachment to the harness and through which opening the flexible load element extends.
13. The height rescue apparatus as claimed in claim 12 wherein the flexible harness element has a loop at each end, which loops are secured relative to the bracket by means of a retained pin received in a further bore in the bracket, recesses being provided in the bracket for receiving the loops of the flexible harness element.
14. The height rescue apparatus as claimed in claim 12 wherein the bracket provides adjacent contact surfaces for the flexible load element and the flexible harness element, which elements extend in opposite directions past each other.
15. The height rescue apparatus as claimed in claim 14 wherein the contact surfaces are smoothly contoured.
16. The height rescue apparatus as claimed in claim 1 wherein the basic form of the bracket is an extrusion.
17. The height rescue apparatus as claimed in claim 1, wherein the flexible elongate element is organised within a housing which is secured relative to the bracket.
18. The height rescue apparatus as claimed in claim 17 wherein the elongate element is wound on a drum mounted for rotation within and relative to the housing, the speed of rotation of the drum being controlled by said at least one speed control means.
19. The height rescue apparatus as claimed in claim 18 wherein said at least one speed control means includes a centrifugal brake mechanism.
20. The height rescue apparatus as claimed in claim 19 wherein said at least one speed control means incorporates a conical brake mechanism.
21. The height rescue apparatus as claimed in claim 20 wherein the centrifugal brake mechanism comprises said drum being threadedly attached to a nut which frictionally engages a drive gear which is resiliently urged towards the nut, the drive gear driving in rotation a shoe drive having shoes mounted thereon for engagement with a corresponding cylindrical friction lining, one or more at least part-conical friction members or segments thereof being provided between the drum and the housing.
22. The height rescue apparatus as claimed in claim 1, wherein the harness incorporates a friction plate and the plate is attached to the housing by one or more resilient flexible members.
23. The height rescue apparatus as claimed in claim 22 wherein the or one of the resilient flexible members comprises a closed loop which extends through an opening in the plate and has its ends looped around retaining posts at opposite sides of the housing.
24. The height rescue apparatus as claimed in claim 22 wherein the apparatus is at least partially enveloped within a resilient pouch which envelopes part of the harness, the harness and an end of the flexible load element projecting from the pouch.
25. The height rescue apparatus as claimed in claim 24 wherein the pouch is made from rubber or synthetic rubber.
26. The height rescue apparatus as claimed in claim 1, wherein the release means is manually or remotely operated.
27. The height rescue apparatus as claimed in claim 26 wherein the release means incorporates a fall switch to detect a fall, release being prevented unless a fall is detected.
28. The height rescue apparatus as claimed in claim 27 wherein the fall switch incorporates a mechanism which acts against a resilient member when the flexible harness element is subjected to a predetermined load.
29. The height rescue apparatus as claimed in claim 1, wherein the load element is releasably secured to the bracket.
Type: Application
Filed: Aug 24, 2007
Publication Date: Nov 11, 2010
Patent Grant number: 8757324
Inventors: Julian Elwyn Renton (Wiltshire), Peter Thomas Mence Nott (Wiltshire)
Application Number: 12/733,315
International Classification: A62B 35/00 (20060101); A62B 1/10 (20060101);